Abstract: A gated peak detector produces phase-independent, magnitude-only samples of an RF signal. Gate duration can span as few as two RF cycles or thousands of RF cycles. Response is linearly proportional to RF amplitude while being independent of RF phase and frequency. A quadrature implementation is disclosed. The RF magnitude sampler can finely resolve interferometric patterns produced by narrowband holographic pulse radar.

Abstract: A frequency modulated continuous wave (FMCW) radar is described. The radar includes a first discriminator for receiving a portion of the swept frequency signal generated by a frequency sweep generator and for producing a reference difference-frequency signal of frequency equal to the difference between the frequency of the swept frequency signal and the frequency of a time displaced swept frequency signal derived from the swept frequency signal. An analogue-to-digital converter is provided for sampling the target difference-frequency signal at a rate derived from the frequency of the reference difference-frequency signal. A processor (88) for determining frequency components of the digitized target difference-frequency signal is arranged to determine for at least one frequency component of the digitized target difference-frequency signal any phase difference between frequency sweeps of said swept frequency signal. The radar may be used for detecting foreign object debris (FOD) on runway surfaces and the like.

Abstract: A system and method for extrapolating sampled radar data allows in one aspect spectral data to be increased without increasing scan time and in another aspect allows scan time to be decreased without decreasing radar data quality. Extrapolation is carried out by extending a sequence of In-Phase and Quadrature-Phase samples by appending additional samples to each end of the sequence. Extrapolated samples are selected to maintain the statistical properties of the original sequence. Applying conventional windowing techniques to the extrapolated sample set results in a weighted extrapolated sequence having a corresponding Doppler spectrum with an increased spectral resolution.

Abstract: Methods and systems consistent with the present invention allow identification of a true signal contained in a signal containing the true signal and noise. In general, digital signal information representing a signal of interest plus noise is utilized by the present invention. The first N samples of digital signal information are stored with the Nth sample being stored in manner which renders it accessible for additional operations. A specially selected set of weights are applied to the buffered N samples and, additionally, phase rotation is applied to the Nth sample. The phase rotated Nth sample and weighted samples are combined using a first equation, described in more detail below. The resulting signal, which exhibits an increased Signal-to-Noise ratio (SNR) and may be more effectively utilized in subsequent MTI processing by virtue of the operations performed on the previous N samples as described herein, is then available for further processing using conventional techniques.

Abstract: Narrow virtual transmit pulses are synthesized by differencing long-duration, staggered pulse repetition interval (PRI) transmit pulses. PRI is staggered at an intermediate frequency IF. Echoes from virtual pulses form IF-modulated interference patterns with a reference wave. Samples of interference patterns are IF-filtered to produce high spatial resolution holographic data. PRI stagger can be very small, e.g., 1-ns, to produce a 1-ns virtual pulse from very long, staggered transmit pulses. Occupied Bandwidth (OBW) can be less than 10 MHz due to long RF pulses needed for holography, while spatial resolution can be very high, corresponding to ultra-wideband (UWB) operation, due to short virtual pulses. X-Y antenna scanning can produce range-gated surface holograms from quadrature data. Multiple range gates can produce stacked-in-range holograms. Motion and vibration can be detected by changes in interference patterns within a range-gated zone.

Abstract: A filter scheme for broadcast interference cancellation that is computationally efficient and numerically robust Airborne Low Frequency Synthetic Aperture Radar (SAR) operating in the VHF and UHF bands has been shown. At least interference Doppler filtering or interference cancellation is utilized. The interference cancellation involves prediction of the interference for each particular reception interval of mixed interference and radar ground response. This prediction is then coherently subtracted from the incoming signal.

Abstract: A method for discrimination of a target from clutter, comprising: providing phase-range data associated with a return pulse of a radar device and second phase-range data associated with a subsequent return pulse; comparing the phase-range data and the second phase-range data to obtain a difference; differentiating the differences with respect to range; and discriminating the target from the clutter by identifying coordinates from the differentiated differences satisfying velocity thresholds associated with the clutter. In one embodiment, the subsequent return pulse is drawn after skipping one or more pulses after the return pulse. In another embodiment, the subsequent return pulse is drawn successive to the return pulse. In other aspects, the invention can be a detection system and/or computer-readable medium adapted implement the method.

Abstract: According to one embodiment, a Doppler radar apparatus includes a quadrature detection unit configured to quadrature-detect a received signal of a reflected pulse from an observation target, and generate time-series data including an in-phase component and a quadrature component, an interference judgment unit configured to judge whether an interference signal is mixed into the received signal based on the time-series data, a correction unit configured to correct a vector expressed by the in-phase component and the quadrature component such that variation with respect to time of a deviation angle of the vector continues when the interference judgment unit has judged that an interference signal is mixed into the received signal, and a calculation unit configured to calculate a Doppler velocity of the observation target based on an amount of variation with respect to time of the deviation angle of corrected vector.

Abstract: Systems and methods are provided for adaptively estimating the specific differential phase (Kdp) from dual-polarization radar data in the complex domain. Some embodiments adapt for wrapped differential propagation phases by estimating the specific differential phase in the complex domain. Some embodiments adapt for measurement fluctuations and/or spatial scale in making such estimations. Some embodiments also provide for determining the presence of storms cells using the dispersion of the differential propagation phase shift over a subset of bins.

Abstract: Provided is a receiving device that is used for a spread spectrum radar apparatus, receives a spectrum-spread signal, and obtains a precise radar spectrum, and includes: a despreading unit that (i) generates first and second despread signals that are generated by despreading a reception signal using a pseudo-noise code, the second despread signal passing through a transmission line carrying a current having a current value identical to a current value of a current carried by a transmission line through which the first despread signal passes, and (ii) includes a first transistor pair including first and second transistors having an identical characteristic, the first transistor outputting the first despread signal, and the second transistor outputting the second despread signal; and a quadrature demodulating unit that generates an in-phase signal and a quadrature signal by quadrature-demodulating the first despread signal and the second despread signal, respectively.

Abstract: A system and method for adaptation of a radar receiver in response to frequency drift in a transmission source is disclosed that utilizes a stable local oscillator established at a single, non-fluctuating frequency and compensates for transmission frequency fluctuation in the signal processor module. The disclosed system and method use mathematical processing techniques to compensate for variations in transmitter frequency during baseband processing of radar reflectivity signals. The system estimates the frequency of the transmitter to a high degree of accuracy and mathematically converts the reflectivity signal energy to a baseband intermediate frequency which is adjusted to compensate for fluctuations in transmitter frequency. A digital down converter circuit and numerically controlled oscillator circuit are also utilized to convert reflectivity signal energy to baseband and compensate for transmitter frequency drift.

Abstract: A radio detection device includes two or more reception antennas, for detecting a detecting object by a mono-pulse method; the radio detection device including: a variable gain unit for discretely changing respective signal intensity of a difference signal and a sum signal of each reception signal received by the two or more reception antennas; an A/D conversion unit for performing A/D conversion process on the difference signal or the sum signal, the difference signal or the sum signal having the signal intensity changed by the variable gain unit; an angle calculating portion for calculating an angle by the mono-pulse method using the difference signal and the sum signal after the A/D conversion process by the A/D conversion unit; and a control unit for performing a control of individually switching a conversion magnification of the signal intensity by the variable gain unit with respect to the difference signal and the sum signal.

Abstract: Distance measuring apparatus has a rough distance measuring circuit (18) using a time delay circuit and a precise distance measuring circuit (31) for measuring the orientation of the vector of a carrier wave to determine the distance, the sum of which is the final output. The rough distance measuring apparatus (18) has a long measurement span but low precision. The precise distance measuring apparatus (31) has a short measurement span but high precision. The combination provides distance measuring apparatus having a long measurement span and high resolution and capable of implementing precise measurement.

Abstract: A linear combiner weight memory. Various embodiments of the weight memory provide a weight bank and control logic. The weight bank is operable to couple with a data stream and may include four registers. The first register is operable to store a first in-phase weight value. The second register is operable to store a second in-phase weight value and be written with the second in-phase weight value while the first in-phase weight value is read from the first register. The third register is operable to store a first quadrature weight value. The fourth register is operable to store a second quadrature weight value and be written with the second quadrature weight value while the first quadrature weight value is read from the third register.

Abstract: A new approach to radar imaging is described herein, in which radar pulses are transmitted with an uneven sampling scheme and subsequently processed with novel algorithms to produce images of equivalent resolution and quality as standard images produced using standard synthetic aperture radar (SAR) waveforms and processing techniques. The radar data collected with these waveforms can be used to create many other useful products such as moving target indication (MTI) and high resolution terrain information (HRTI). The waveform and the correction algorithms described herein allow the algorithms of these other radar products to take advantage of the quality Doppler resolution.

Abstract: A radar warning receiver is implemented in low cost integrated circuit form utilizing only one analog component, namely a limiting amplifier. By taking the output of the limiting amplifier and utilizing monobit sampling of the output it has been found that one can provide an integrated circuit single chip radar warning receiver using delay correlation to extract frequency, amplitude and modulation type from signals at or below the noise level.

Abstract: A new approach to radar imaging is described herein, in which radar pulses are transmitted with an uneven sampling scheme and subsequently processed with novel algorithms to produce images of equivalent resolution and quality as standard images produced using standard synthetic aperture radar (SAR) waveform and processing techniques. The radar data collected with these waveforms can be used to create many other useful products such as moving target indication (MTI) and high resolution terrain information (HRTI). The waveform and the correction algorithms described herein allow the algorithms of these other radar products to take advantage of the quality Doppler resolution.

Abstract: The system is a parallel processing jamming architecture that is designed to automatically attack and concurrently investigate multiple signals simultaneously in the radio environment. The system implements multiple wideband independent channels to allow simultaneous threat signals to be processed in parallel and jammed in real-time. The system automatically attacks a radio communication channel when the suspect radio signal surpasses a dynamic composite threshold which is internally updated using multi-channel data feedback, in real-time. The concurrent analysis with transmission allows the system to optimize the jam efficiency quickly to an unknown signal, and while determining the validity of the threat. The high throughput parallel architecture allows the intelligent jamming process to occur with rapidity and signal multiplicity.

Abstract: A digitally tuned digital radio frequency memory that captures a portion of a first radio frequency signal and retransmits the portion as a coherent radio frequency signal. The digitally tuned radio frequency memory may include a track and hold configured to track and hold the first radio frequency signal and to output a shaped signal; a digitizer configured to convert the shaped signal to a digital word; a memory configured to store the digital word; and a direct digital frequency synthesizer configured to provide a sampling clock signal, wherein the sampling clock signal is provided to the track and hold.

Abstract: A method of extracting a radial velocity characteristic of a target from coherent pulse bursts comprising the steps of applying to data a ‘best fit’ model of the echo returns from a target in the presence of clutter to obtain a residue (error) value and minimising the error value by a predetermined method to give the best fit value for the target radial velocity. The method enables more information to be retrieved from coherent bursts than conventional methods and therefore greatly enhances performance of radiation pulse echo detection.

Abstract: A device and method for measuring phase and power shifts in a simultaneous dual polarization radar system comprises an access port, a quadrature mixer, and a power detector. The access port is configured to couple to the simultaneous dual polarization radar system near the antenna of the simultaneous dual polarization radar system. The quadrature mixer is configured to mix a first signal from a first polarization and a second signal from a second polarization. The first signal and the second signal are sampled through the access port. The first power detector is configured to measure the power level of the first signal.

Abstract: One preferred embodiment of the present invention provides a system and method for suppressing motion interference in a radar detection system. Briefly described, in architecture, one embodiment of the system, among others, can be implemented as follows. The system includes a signal generator that transmits microwave signals toward a target area. Also, the system includes a data control system to collect data from reflected microwave signals from the target area and to analyze the data in order to suppress unwanted motion interference generated by movement of the radar detection system. Other systems and methods are also provided.

Abstract: A method for target detection and angle estimation in a radar system includes receiving a signal from a radar array; based on the received signal, performing monopulse beamforming to obtain one or more monopulse beams; based on the monopulse beams, determining monopulse ratios; using maximum likelihood estimation based on the determined monopulse ratios to determine a monopulse ratio estimate corresponding to a maximum of a likelihood function; accessing a table correlating monopulse ratio estimates and target angle values and determining from the table an estimated target angle; accessing a complex target amplitude corresponding to the estimated target angle, comparing the complex target amplitude to a threshold; and if, based on the step of comparing, the target amplitude exceeds the threshold, providing an output signal indicative of target detection and the estimated target angle.

Abstract: Systems and methods are provided for determining first and second azimuth angle values representing two closely spaced targets. Monopulse radar scan data is produced and processed to provide quadrature angle data, merged azimuth angle data, and a maximum magnitude of the quadrature angle. A quadrature angle methodology that derives the first and second azimuth angle values from an integration of the quadrature angle data over an angular region within the monopulse scan is applied if the maximum quadrature angle magnitude exceeds the threshold value. A merged azimuth angle methodology that fits the merged azimuth angle data to a polynomial as a function of a boresight angle of the monopulse radar to derive the first and second azimuth angle values is applied if the maximum quadrature angle magnitude does not exceed the threshold value. The first and second azimuth angle values are then displayed to a user.

Abstract: A quadrature radar apparatus includes a quadrature signal generating unit, a plurality of coupler modules connected to the signal generating unit, an antenna unit receiving transmission signals from the coupler modules and a reception signal reflected from a target, one or more phase delay modules connected between one or more of the coupler modules and the antenna unit to delay the phases of the transmission and reception signals by 90 degrees, a leakage signal canceling unit combining the reception signals inputted from the antenna unit through the first and second coupler modules and removes the transmission leakage signal.

Abstract: A millimeter wave image processor, capable of performing imaging by matching and filtering while considering a spherical wave on an antenna face in a near field, is provided. The processor includes: a T-antenna which receives a radio wave emitted by a target; an A/D converter which A/D converts signals received by the T-antenna; a correlation processing unit which performs correlation processing to a combination of signals of a horizontal conversion output and a vertical conversion output among A/D converted data; and an imaging processor which correlates a reference function in which a received signal is generated theoretically on an assumption that the target is at a position of a focused distance and a received signal of a spherical wave received by the T-antenna for each pixel in the field of view to thereby create an image of the target.

Abstract: A target object motion estimation method using at least one subset of a complex SAR image. Coarse range cell alignment is performed on at least one subset of a complex SAR image. At least one subset is autofocused, thereby providing an estimated phase error function. The estimated phase error function yielded by autofocusing (or a manipulated version of the phase error function) may be analyzed to detect, characterize, and estimate target object motion.

Abstract: A radar signal processing system utilizing a specialized neural network generative topographic mapping method which employs an alternative method for characterizing multiple radar signatures wherein specialized phased-codes and wavelet waveform modulations are used. The invention comprises three layers each including a plurality of nodes: input layer, mapping layer, and output presentation layer. The input layer takes the collected signals and congregates them into groups of linear data points. The mapping layer provides a method for projecting the data into points of lower dimensions. The data is assumed to arise by first probabilistically picking a point in a low-dimensional space, mapping the point to be observed in high-dimensional input space, then adding noise. The result is a system in which radar data with multiple reflections in close proximity is manipulated into multiple signatures in systematic ways for use in downhole structure signatures.

Abstract: Communication between a remote locator and a transponder is used to determine the relative position of the transponder. The transponder and locator each include a transmitter and a receiver. The locator transmits an inquiry in the form of a relatively powerful cyclically encoded signal with repetitive elements, uniquely associated with a target transponder. Periodically, each transponder correlates its coded ID against a possible inquiry signal, determining frequency, phase and framing in the process. Upon a match, the transponder transmits a synthesized response coherent with the received signal. The locator integrates multiple cyclical response elements, allowing low-power transmissions from the transponder. The locator correlates the integrated response, determines round-trip Doppler shift, time-of-flight, and then computes the distance and angle to the transponder. The transponder can be wearable, bionically implanted, or attached to, or embedded in, some object.

Abstract: A method of obtaining in-phase and quadrature phase components for a narrowband signal is provided. The method includes digitally sampling a narrowband signal at a digital sampling rate to obtain a number of data points. The method subtracts a first portion of the data points corresponding to a first half of one period of the signal from a second portion of the data points corresponding to a second half of the one period of the signal to obtain a number of output data points which is less than the number of data points obtained from sampling the narrowband signal.

Abstract: A radar system and method that employs polarization-time diversity in transmitting signals and concurrently processing received reflections from both polarization modes provides information about the scattering matrix of a target without loss of information. Illustratively, the transmitted signals from Golay pairs, and the processing method employs a complex-conjugate time reversal operand. The received reflected signals are processed for a particular distance in mind to develop a scattering matrix of the medium at that distance. By comparing the scattering matrix to known scattering matrices an identification of the target from where the transmitted signals were reflected is obtained.

Abstract: Channel quality can be detected accurately in a wireless transmission system such as an HSDPA method. In the case of estimating a channel quality of a signal transmitted by a Code Division Multiple Access method and of estimating the channel quality in a system having a synchronization channel not orthogonal to a channel receiving data, a noise component of a desired channel is estimated; degree of a noise component caused by the synchronization channel is estimated with respect to the estimated noise; and a channel quality of a receiving channel is detected based on the estimated degree of the noise component.

Abstract: A frequency modulated continuous wave (FMCW) radar is described. The radar includes a first discriminator for receiving a portion of the swept frequency signal generated by a frequency sweep generator and for producing a reference difference-frequency signal of frequency equal to the difference between the frequency of the swept frequency signal and the frequency of a time displaced swept frequency signal derived from the swept frequency signal. An analogue-to-digital converter is provided for sampling the target difference-frequency signal at a rate derived from the frequency of the reference difference-frequency signal. A processor (88) for determining frequency components of the digitized target difference-frequency signal is arranged to determine for at least one frequency component of the digitized target difference-frequency signal any phase difference between frequency sweeps of said swept frequency signal. The radar may be used for detecting foreign object debris (FOD) on runway surfaces and the like.

Abstract: A computer system for compressing synthetic aperture radar (SAR) images includes a database for storing SAR images to be compressed, and a processor for compressing a SAR image from the database. The compressing includes applying an anisotropic diffusion algorithm to the SAR image, and compressing the SAR image after applying the anisotropic diffusion algorithm thereto. Applying the anisotropic diffusion algorithm includes determining noise in the SAR, selecting a noise threshold for the SAR image based on the determined noise, and mathematically adjusting the anisotropic diffusion algorithm based on the selected noise threshold.

Abstract: Systems and methods that adapt to the weather and clutter in a weather radar signal and apply a frequency domain approach that uses a Gaussian clutter model to remove ground clutter over a variable number of spectral components that is dependent on the assumed clutter width, signal power, Nyquist interval and number of samples. A Gaussian weather model is used to iteratively interpolate over the components that have been removed, if any, thus restoring any overlapped weather spectrum with minimal bias caused by the clutter filter. The system uses a DFT approach. In one embodiment, the process is first performed with a Hamming window and then, based on the outcome, the Hamming results are kept or a portion of the process is repeated with a different window. Thus, proper windows are utilized to minimize the negative impact of more aggressive windows.

Abstract: A quadrature radar apparatus includes a quadrature signal generating unit, a plurality of coupler modules connected to the signal generating unit, an antenna unit receiving transmission signals from the coupler modules and a reception signal reflected from a target, one or more phase delay modules connected between one or more of the coupler modules and the antenna unit to delay the phases of the transmission and reception signals by 90 degrees, a leakage signal canceling unit combining the reception signals inputted from the antenna unit through the first and second coupler modules and removes the transmission leakage signal.

Abstract: A new approach to radar imaging is described herein, in which radar pulses are transmitted with an uneven sampling scheme and subsequently processed with novel algorithms to produce images of equivalent resolution and quality as standard images produced using standard synthetic aperture radar (SAR) waveform and processing techniques. The radar data collected with these waveforms can be used to create many other useful products such as moving target indication (MTI) and high resolution terrain information (HRTI). The waveform and the correction algorithms described herein allow the algorithms of these other radar products to take advantage of the quality Doppler resolution.

Abstract: Sensing vehicle speed is disclosed. A speed sensor is self powered. The speed sensor measures a speed data of multiple vehicles with one Doppler pulse. A sample is taken of speed sensor data from the speed sensor. The sample of speed sensor data is processed to calculate speed. The calculated speed is wirelessly transmitted to a server.

Abstract: A quadrature transmitter and receiver have configurable I and Q channel paths that facilitate the application of selected test signals to determine gain and phase imbalances introduced by the transmitter and receiver. In a first ‘normal’ configuration, the I and Q channels are independently tested by applying an I-only test signal, followed by a Q-only test signal. In a second ‘switched transmitter’ configuration, the Q-only test signal is again applied. In a third ‘switched receiver’ configuration, the I-only test signal is again applied. By combining the results, gain and phase imbalances of the transmitter and the receiver can be determined. In a preferred embodiment, these configurations and test signals are applied within a single transceiver that has the output of its transmitter closed-loop coupled to the input of its receiver.

Abstract: A filter scheme for broadcast interference cancellation that is computationally efficient and numerically robust Airborne Low Frequency Synthetic Aperture Radar (SAR) operating in the VHF and UHF bands has been shown. At least interference Doppler filtering or interference cancellation is utilised. The interference cancellation involves prediction of the interference for each particular reception interval of mixed interference and radar ground response. This prediction is then coherently subtracted from the incoming signal.

Abstract: A wavefront curvature effect associated with a complex image produced by a synthetic aperture radar (SAR) can be mitigated based on which of a plurality of possible flight paths is taken by the SAR when capturing the image. The mitigation can be performed differently for different ones of the flight paths.

Abstract: For enabling determination on whether a sign of a Doppler frequency or a target angle is positive or negative even when only a real signal can be obtained as a received signal, the present invention provides a radar device including: an oscillator; a transmitting element; a distributor; receivers using the local wave to detect the received wave to generate a real received signal; a plurality of inter-channel phase correcting units; a spatial frequency information generating unit for converting a received signal string obtained by gathering a plurality of phase-corrected received signals into a signal in a spatial frequency domain; and a sign selecting unit for selecting a signal having a larger amplitude in a spatial frequency spectrum when two signals from a positive direction and a negative direction which are symmetrical with respect to a direction at approximately 0 degree.

Abstract: A method and receiver are disclosed for mitigating or substantially canceling signal interference between signals detected at the receiver. Once a presumed interfering signal(s) is acquired, parameters are determined that allow the interferer(s) to be modeled. The phase invariance of the process eliminates the need to acquire the interferer's phase. An orthogonal projection (for projecting onto a detection subspace which is orthogonal to a subspace spanned by the interferer(s)) is applied to the composite of all signals (y) for thereby projecting y onto the detection subspace. The interference subspace is non-orthogonal to a representation of desired (but interfered) signal of the composite signals. With the receiver properly equipped to perform this projection operation, interfering signals, multipath, multipath-like, and structured jamming signals can be effectively diminished.

Abstract: A computer system for decompressing synthetic aperture radar (SAR) images includes a database for storing SAR images to be decompressed, and a processor for decompressing a SAR image from the database. The decompressing includes receiving the SAR image, performing a dynamic range compression on the SAR image, and quantizing the compressed SAR image. The quantized compressed SAR image is then decompressed by applying an anistropic diffusion algorithm thereto.

Abstract: The frequency modulation radar device includes a transmitting unit (5), M receiving units for receiving a reflected signal as M channels, a mixing unit (7) for mixing the transmitting signal with the M received signals to obtain beat signals for the M channels, a frequency analyzing unit (9) for analyzing the beat signals for the M channels in frequency, and a calculating unit (1) for calculating a distance to a target object and an orientation angle based on frequency analysis results. The calculating unit (1) calculates a noise level from the frequency analysis result, extracts a peak signal of a subject target object in each of the channels based on the calculated noise level to generate a covariance matrix, discriminates between a signal eigenvalue and a noise eigenvalue among M eigenvalues of the covariance matrix, and estimates the number of incident signals based on the number of signal eigenvalues.

Abstract: A radar device includes: an oscillator for generating a wave at a plurality of transmission frequencies; a transmitting antenna; a receiving antenna; a receiver for generating a real received signal; a Fourier transform unit for performing a Fourier transform on the real received signal in a time direction; a spectral peak detecting unit for receiving an input of a result of the Fourier transform to extract peak complex signal values of Doppler frequency points having a maximum amplitude; a distance calculating unit for storing the peak complex signal values and for calculating a distance to a reflecting object based on the stored peak complex signal values to output the obtained distance as a measured distance value; and a distance sign determining unit for determining validity of the measured distance value and for outputting the measured distance value and the Doppler frequency according to a result of determination.

Abstract: Provided is a receiving device that is used for a spread spectrum radar apparatus, receives a spectrum-spread signal, and obtains a precise radar spectrum, and includes: a despreading unit that (i) generates first and second despread signals that are generated by despreading a reception signal using a pseudo-noise code, the second despread signal passing through a transmission line carrying a current having a current value identical to a current value of a current carried by a transmission line through which the first despread signal passes, and (ii) includes a first transistor pair including first and second transistors having an identical characteristic, the first transistor outputting the first despread signal, and the second transistor outputting the second despread signal; and a quadrature demodulating unit that generates an in-phase signal and a quadrature signal by quadrature-demodulating the first despread signal and the second despread signal, respectively.

Abstract: A method of obtaining in-phase and quadrature phase components for a narrowband signal is provided. The method includes digitally sampling a narrowband signal at a digital sampling rate to obtain a number of data points. The method subtracts a first portion of the data points corresponding to a first half of one period of the signal from a second portion of the data points corresponding to a second half of the one period of the signal to obtain a number of output data points which is less than the number of data points obtained from sampling the narrowband signal.

Abstract: A computer system for processing synthetic aperture radar (SAR) images includes a database for storing SAR images to be processed, and a processor for processing a SAR image from the database. The processing includes determining noise in a SAR image to be processed, selecting a noise threshold for the SAR image based on the determined noise, and mathematically adjusting an anisotropic diffusion algorithm based on the selected noise threshold. The adjusted anisotropic diffusion algorithm is applied to the SAR image.

Abstract: Radar systems are disclosed that include a signal generator, an antenna, a switching circuit, an I/Q sampling and signal-demodulation (demodulation) processor, and a FFT processor. The signal generator produces energization signals. The antenna has multiple individual antenna elements. The switching circuit is configured to deliver the energization signals to a selected antenna element at a respective moment in time to cause the selected antenna element to transmit a respective radar signal in response to the energization signal. At least one element receives a corresponding return-radar signal before the switching circuit selects a next antenna element to transmit a respective radar signal. The demodulation processor receives the return-radar signals from the antenna elements and demodulates the return-radar signals. The FFT processor fast-Fourier transforms the return-radar signals.